The present invention relates to a liquid crystal display-specific substrate having a phase difference control function and a liquid crystal display using the same, and more particularly to a liquid crystal display-specific substrate having a phase difference control layer patterned in a liquid crystal cell and a liquid crystal display using the same.
Having low-profile, low-mass, low power consumption and flickerless features, color liquid crystal displays (hereinafter referred to as LCD for a liquid crystal display) have boomed especially for notebook PCs. More recently, demand is growing for desktop monitors larger than notebook PCs as part of such PC-dedicated displays. LCDs are now used not only for PCs, but also for TVs for which CRTs have so far been mainly employed.
A grave problem with LCDs is a limited viewing angle. This is because when an LCD is viewed from an oblique direction, there is leakage of light from some pixels designed originally for black displays, which otherwise causes inversion of contrast, ending up with improper displays. With such defects in mind, there is developed a wide-viewing angle, vertical alignment mode LCD using a retardation film, which is free from any light leakage even with viewing angle increases in black display pixels, as set forth in Patent Publication 1 and Patent Publication 2.                Patent Publication 1        JP-A 10-153802        Patent Publication 2        JP-A 11-258605        Patent Publication 3        JP-A 7-258638        Patent Publication 4        JP-A 10-508882        
Commonly, such a retardation film is affixed to a polarizing plate with optical axes positioned at a specific angle (an absorption axis in the case of the polarizing plate and an optical axis in the case of the retardation film). However, there is a low display contrast due to the interfacial reflection of light, because the refractive index of the adhesive used therewith is lower than those of the polarizing plate and retardation film.
With phase difference compensation having associated chromatic dispersion, compensation is generally made with emphasis on a specific wavelength. Often, phase difference compensation is performed with emphasis on green having the highest spectral luminous efficacy. For this reason, black display pixels can never be displayed in perfectly pure black, with leakages of red and blue light components, resulting in purplish black displays.
Another defect of the retardation film is that screen distortion occurs when applied to LCDs, because its volume varies upon absorption of moisture, causing phase difference variations. The larger the area of the retardation film, the more outstanding this tendency becomes, offering a particular problem in conjunction with liquid crystal TVs now under development in many aspects.